Electrically-powered machines such as motors typically have an electrical cable connected to a conductive terminal of an electrical plug that can be engaged with an electrical receptacle of a power source to energize the machine.
It may be desirable to prevent a plug from being disengaged from a receptacle. For example, industrial receptacle panels typically have several receptacles, each of which are engaged by a plug of a different machine. If an operator mistakenly disengages the plug of a motor from the receptacle, but the plug is supposed to remain engaged, this may unexpectedly disrupt the supply of electric current to the motor.
It may also be desirable to prevent a plug from being engaged with a receptacle. For example, an operator may intentionally disengage the plug of a motor from the receptacle to prevent electrically-powered movement of a rotor while the machine is being serviced. A different operator may be unaware that the motor is being serviced and re-engage the plug of the motor with the receptacle. The unexpected supply of electric current to the motor is potentially dangerous for persons who are servicing the motor.
Accordingly, there is a need in the art for a safety device that prevents an electrical plug from being disengaged from an electrical receptacle, or that prevents an electrical plug from being engaged with an electrical receptacle. Such a device is preferably simple and economical to manufacture, and reliable and convenient in use.